Dissipating heat within housings for electrical components

ABSTRACT

Embodiments of various electrical housings, particularly display housings, are provided. In this regard, a representative housing, among others, includes one or more electrical components that are disposed at the housing; a thermal attachment that is designed to transfer heat generated by the one or more electrical components; and a rear enclosure that is designed to engage the thermal attachment. The rear enclosure is further designed to dissipate the heat received from the thermal attachment.

TECHNICAL FIELD

The present disclosure relates to housings for electrical components,and more particularly, the disclosure relates to dissipating heatgenerated within a display housing.

BACKGROUND

Conventional clamshell computer systems place a video controller andcentral processing unit (CPU) nearby in the base. The display refreshsignals connect to a display housing. Heat generated by the videocontroller is dissipated in the base of the clamshell computer, with theheat dissipated in the display housing. The base of the clamshellcomputer is typically designed and constructed to connect and dissipatethe heat from the combination of CPU and video controller.

Liquid cooling systems have sought to take advantage of the largepassive area of the display rear enclosure to dissipate heat. Thosesystems transfer heat from the base through the hinge cavity (usingthermally conductive material, including water) and then radiate theheat passively across the surface of the display housing. However, thespace that is used for the video graphics adapter (VGA) controllercircuitry and its thermal evacuation may be substantial, increasing thesize of the base of the clamshell computer. Typically, a small or thinbase size is attractive to a user. In addition, thermal evacuation onthe base places the heat on the lap of a user and the fans used toremove the heat make noise which may be unattractive.

SUMMARY

Embodiments of various electrical housings, particularly displayhousings, are provided. In this regard, a representative housing, amongothers, includes one or more electrical components that are disposed atthe housing; a thermal attachment that is designed to transfer heatgenerated by the one or more electrical components; and a rear enclosurethat is designed to engage the thermal attachment. The rear enclosure isfurther designed to receive and dissipate the received heat from thethermal attachment.

Other systems, methods, features, and advantages of the presentinvention will be or become apparent to one with skill in the art uponexamination of the following drawings and detailed description. It isintended that all such additional systems, methods, features, andadvantages be included within this description, be within the scope ofthe present invention, and be protected by the accompanying claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the disclosure can be better understood with referenceto the following drawings. The components in the drawings are notnecessarily to scale, emphasis instead being placed upon clearlyillustrating the principles of the present disclosure. Moreover, in thedrawings, like reference numerals designate corresponding partsthroughout the several views.

FIG. 1 is a perspective view of an embodiment of a clamshell computer.

FIG. 2 is a schematic view of a clamshell computer, such as that shownin FIG. 1.

FIG. 3 is a preassembled view of a top housing of a clamshell computer,such as that shown in FIG. 1, having a thermal attachment.

FIG. 4 illustrates a hot spot on a top housing of a clamshell computer,such as that shown in FIG. 1.

FIG. 5 illustrates an ideal heat distribution across a rear enclosure ofa clamshell computer, such as that shown in FIG. 4.

FIG. 6 is a perspective view of an embodiment of a thermal attachment,such as that shown in FIG. 3.

FIG. 7 is a perspective view of another embodiment of a thermalattachment and a rear enclosure, such as that shown in FIG. 3, thatinclude isolating members that thermally isolate the thermal attachmentfrom the rear enclosure.

FIG. 8 includes a preassembled view and a cross-sectional view ofanother embodiment of a thermal attachment and rear enclosure, such asthat shown in FIG. 3, that decrease thermal resistance to the rearenclosure.

FIG. 9 includes an assembled view and a cross-sectional view of anotherembodiment of the thermal attachment and rear enclosure, such as thatshown in FIG. 8.

FIG. 10 is a schematic view of another embodiment of a clamshellcomputer, such as that shown in FIG. 1.

DETAILED DESCRIPTION

Exemplary systems are first discussed with reference to the figures.Although these systems are described in detail, they are provided forpurposes of illustration only and various modifications are feasible.

FIG. 1 is a perspective view of an embodiment of a clamshell computer100. The clamshell computer 100 generally has two (2) pieces, e.g., atop housing 105 and a base 110, joined by a hinge 115. The top housing105 includes a display device 120, and the base 110 includes a centralprocessing unit (CPU), battery, hard drive, etc. (not shown). Cables(not shown) communicate display data and power from the base 110 to thetop housing 105. The video graphics adapter (VGA) controller 125 isgenerally located in the top housing 105.

It should be noted that a clamshell computer is generally different froman “all in one” computer, where electrical functions are locatedtogether in the top housing. Typical examples of an “all in one” are theSony W101, the Apple iMac, and tablet computers (also known as “slate”).In this disclosure, the clamshell computer has some software computationperformed at the base 110. It is possible that the method and system ofdissipating heat described in this disclosure can be utilized in the“all in one” computer.

FIG. 2 is a schematic view of the clamshell computer 100, such as thatshown in FIG. 1. The top housing 105 includes a liquid crystal display(LCD) 205 that is electrically coupled to the VGA controller 125 via,for example, a low-voltage differential signaling (LVDS) link or aDisplayPort 210. The display 205 generally has no memory; the displaylink or port 210 can be a unidirectional bus carrying data to the LCD205. The VGA controller 125 is generally electrically coupled to a CPU215 and main memory 225 via, for example, a peripheral componentinterconnect express (PCI-E) bus 220. The VGA controller 125 is anengine that creates a visual page from a CPU instruction.

A memory or a frame buffer (not shown) is located near the VGAcontroller 125. The frame buffer holds the constructed image. Theprocess of writing to the display 205 involves the VGA controller 125repeatedly accessing the frame buffer data, pixel by pixel, then line byline, and transferring to the display 205. The speed of the data acrossthe link or port 210 is a function of the color depth of the display205, the display resolution, and the refresh rate of the image.

With electrical components in the top housing 105, heat can be createdin the top housing 105 directly and dissipated there from the base 115.The heat can spread to the top surface of the top housing 105 so as toavoid a “hot spot” on the rear of the top housing 105 that would beuncomfortable to a touch of the user.

FIG. 3 is a preassembled view of a top housing of a clamshell computer,such as that shown in FIG. 1, having a thermal attachment. The tophousing 105 includes the VGA controller 125 that is disposed between theLCD 205 and a thermal attachment 310. The VGA controller 125 is placedon a separate printed circuit board (PCB) and is mounted on a topsurface of a rear enclosure 305 via PCB fasteners 320. The thermalattachment 310 includes holes 315 that register with the PCB fasteners320. Alternatively or additionally, the VGA controller 125 may belocated along with the LCD display 205 itself. The thermal attachment310 is disposed between the VGA controller 125 and the rear enclosure305, so heat is transferred from the VGA controller to the rearenclosure 305, where heat meets cooler ambient air. The thermalattachment 310 covers a portion of the inner surface area of the rearenclosure 305. The thermal attachment 310 is further described inrelation to FIGS. 5-7.

FIG. 4 illustrates a hot spot on a top housing of a clamshell computer100, such as that shown in FIG. 1. Attaching a heat source, e.g., VGAcontroller 125, to a single point has potential limitations. The thermalresistance of many materials is linearly proportional to its thickness.The top housing 305 is generally thin (approximately one (1) or two (2)millimeters thick) and wide such that the thermal resistance in the Xand Y direction is relatively higher than in the Z direction.Accordingly, attachment of a heat source to the rear enclosure 305 cancreate a localized hot spot 425 on the opposite side of the rearenclosure 305. The amount of power dissipated can be limited by themaximum temperature allowed on the user-touchable surface of the rearenclosure 305. This can limit the graphics performance of the clamshellcomputer 100, since graphics performance of the clamshell computer 100is proportional to the amount of power that the clamshell computer 100consumes.

Heat convection generally favors heat traveling upward towards a topedge 405 of the top housing 105, making the bottom edge 410 of the tophousing 105 cooler. Also, the conduction of heat via the hinges 115ensures that the bottom edge 410 of the rear enclosure 305 is coolerthan the top edge 405. Since thermal resistance is linear to dimension,the corners 415 of the clamshell computer 100 are generally cooler thanthe middle edges 420 of the rear enclosure 305. The combination of theseforces generally means that a “hot spot” 425 is created. Eliminating thehot spot 425 (and dissipating the heat more evenly over the broadestpossible surface area) is a challenge that is addressed in thisdisclosure. FIG. 5 illustrates an ideal distribution across the rearenclosure 305, in which heat is distributed evenly across the wholesurface of the rear enclosure 305.

FIG. 6 is a perspective view of an embodiment of a thermal attachment610, such as that shown in FIG. 3. The thermal attachment 610 can bemade of graphite material that is capable of distributing temperature;whereas, most material (plastic, air, metal) is generally thermallyconductive no matter the orientation. In addition, graphite can beformed into sheets that are highly conductive in a plane and moderatelyconductive in other directions. For example, a graphite sheet may behighly conductive (1000 W/mK) in the flat X-Y direction, but moderatelyconductive (50 W/mK) in the thin Z direction. So, graphite can be usedto “steer” heat, especially for the purpose of decreasing touchtemperature and dissipating the hot spot 425 (FIG. 4) by spreading theheat uniformly among a broad surface, generally before conducting to thesurface of the rear enclosure 305.

However, using a graphite sheet has some disadvantages. For example, thegraphite sheet is not of uniform temperature. Though the graphite ishighly thermally conductive, the longer distances, especially thecorners, are generally cooler. Also, thermal conductivity depends on thethickness of the material, and it may be attractive to maintain a thindisplay enclosure. In addition, the contact point where the VGAcontroller 125 attaches to the graphite sheet can be the hottestlocation. Further, conduction in the Z plane may be lower than optimal,to transfer heat to the enclosure rear surface.

Thermal conductivity of the graphite sheet can be controlled by apattern of perforations 625. In this example, heat is steered toward thecorners by introducing perforation patterns 625 in the area of thehighest heat flow. The perforations patterns 625 are designed andarranged in a triangular shape, where the bases 630 of the perforatedtriangles 625 are adjacent to the side edges of the thermal attachment610 and the top corners 635 of the perforated triangles 625 are pointingtoward the center of the thermal attachment 610. Alternatively oradditionally, the perforated patterns can have other geometric shapes,such as, diamond, square, heptagon, and other polygonal shapes.

The perforations 625 at the top corners 635 of the perforated trianglesare larger than the perforations 625 at the bases 630. The size of theperforations gradually increases from the base 630 to the top corner635. The perforations 635 can cause interruptions of the thermalconduction. In this case, a heat source located in the middle of the tophousing 105 can promote heat flow to the cooler corners of the tophousing 105.

The contact area of the VGA controller 125 to the thermal attachment 610can be the highest temperature point. The rest of the rear enclosure 305can be highly conductive if the rear enclosure 305 is made of magnesiumor aluminum and not plastic. The enclosure area opposite the contactarea is isolated from the hot spot 425 by any of the following methods,among others:

-   -   a. the center of the rear enclosure 305 is recessed or dished        620 (so as not to make contact with the graphite sheet).    -   b. an insulative material (not shown), e.g, a poor thermal        conductor such as rubber foam, is positioned between the thermal        attachment 610 and the rear enclosure 305.    -   c. a decoration (not shown) made of relatively poorly conducting        material is placed on the outside of the rear enclosure 305. The        decoration can include the clamshell computer logo.

FIG. 7 is a perspective view of another embodiment of a thermalattachment 710 and a rear enclosure 705, such as that shown in FIG. 3,that include isolating members that thermally isolate the thermalattachment 710 from the rear enclosure 705. The isolating members 715,720 facilitate controlling contacts between the thermal attachment 710and the rear enclosure 705. The isolating member 715, 720 can berecesses 715, 720 which thermally isolate the thermal attachment 710.The recesses 715, 720 could be formed on the inner surface 725 of therear enclosure 705.

A patterned conductive sheet (not shown) could be applied in between thethermal attachment 710 and rear enclosure 705. Lastly, thermallyconductive adhesive could be applied to control the conduction of heatfrom the thermal attachment 710 to the rear enclosure 705. In thisexample, the isolating member 715 includes multiple parallel recesses ina diamond shape and the isolating member 720 includes multiple parallelrecesses in a triangular shape, both having a corner pointing towardsthe side edge of the rear enclosure 705. However, the isolating member715 can have other geometric shapes, such as, square, heptagon, andother polygonal shapes

FIG. 8 includes a preassembled view and a cross-sectional view ofanother embodiment of a thermal attachment 810 and rear enclosure 805,such as that shown in FIG. 3, that decrease thermal resistance to therear enclosure 805. The rear enclosure 805 has a pattern of thermalridges 820 disposed on the inner surface 825 of the rear enclosure 805.The thermal attachment 810 has a complementary pattern of slots 815 thatregisters with the pattern of thermal ridges 820. In this example, twosets of patterned thermal ridges 820 are disposed at the top left cornerand bottom right corner of the rear enclosure 805. Each pattern ofthermal ridges 820 includes three separate and elongated ridges. Amiddle ridge is positioned diagonally from the corner of the rearenclosure 805 towards the center of the rear enclosure 805. Left andright ridges are placed substantially parallel to the middle ridge.

FIG. 9 includes an assembled view and a cross-sectional view of anotherembodiment of a thermal attachment 810 and rear enclosure 805, such asthat shown in FIG. 8. It should be noted that tight contact is generallymade between the thermal attachment 810 and the rear enclosure 805 viathe slots 815 and the thermal ridges 820. To avoid air gaps, aconductive paste or epoxy (not shown) may be used to fill the gapbetween the thermal attachment 810 and the rear enclosure 805. Theconduction of heat in the Z direction may be limited, so that thetemperature of the rear enclosure 805 is cool to the touch even when theVGA controller 125 (FIG. 1) is hot. The thermal attachment 810 conductsheat generated within the top housing 105 (FIG. 1) and interspersesthermal contacts to the X/Y plane of the thermal attachment 810. Heatflow within the thermal attachment 810 can travel towards the thermalridges 820 and slots 815 as indicated with arrow 830. The thermal ridges820 act as channels for heat to flow to the outside of the rearenclosure 805 as indicated with arrow 840. These are positioned in areaswhere heat should be steered normally towards the cooler areas, such asthe corners. In addition, heat flow can travel from the thermalattachment 810 to the inner surface 825 of the rear enclosure 805 asindicated with arrow 835. It should be noted that the heat flow 840 isgenerally higher as compared to the heat flow 835.

FIG. 10 is a schematic view of another embodiment of a clamshellcomputer, such as that shown in FIG. 1, and is denoted generally byreference number 1000. The design and architecture of the clamshellcomputer 1000 is similar to the clamshell 100 (FIG. 2), which includestop housing 105, LCD 205, hinge 115, base 110, first VGA controller 125,CPU 215, main memory 225, and link/port 210. However, the clamshellcomputer 1000 further includes a second VGA controller 1005 at the base110. It is possible to have multiple VGA controllers in a computingsystem. For clamshell computers, a particular solution is calledHybrid™, SLI™ or CrossFire™. Physically distinct video controllers maybe used together or Individually to render 3D graphics. It may still bedesirable to position the first VGA controllers at the top housing 105and the second VGA controller 1005 at the base 110. In any computingsystem designs, the thermal attachment and the rear enclosure mentionedcan be used to dissipate heat generated at the top housing.

This description has been presented for purposes of illustration anddescription. It is not intended to be exhaustive or to limit thedisclosure to the precise forms disclosed. Obvious modifications orvariations are possible in light of the above teachings. The embodimentsdiscussed, however, were chosen to illustrate the principles of thedisclosure, and its practical application. The disclosure is thusintended to enable one of ordinary skill in the art to use thedisclosure, in various embodiments and with various modifications, as issuited to the particular use contemplated. All such modifications andvariation are within the scope of this disclosure, as determined by theappended claims when interpreted in accordance with the breadth to whichthey are fairly and legally entitled.

What is claimed:
 1. A clamshell computer comprising: a base; and a tophousing that is attached to the base via at least one hinge, the tophousing including a thermal attachment that engages a rear enclosure ofthe top housing, the thermal attachment being designed to conduct heattowards the rear enclosure, wherein the base includes a processing unitthat is electrically coupled to memory, the top housing including avideo controller that is electrically coupled to the processing unit andmemory, the video controller being electrically coupled to a displaydevice, the video controller being placed between the thermal attachmentand the display device, the thermal attachment being placed between thevideo controller and the rear enclosure.
 2. The clamshell computer asdefined in claim 1, wherein the thermal attachment covers a portion ofthe inner surface area of the rear enclosure and is made of materialscapable of distributing temperature, the thermal attachment including apattern of perforations that is designed to steer heat towards thecorners of the rear enclosure.
 3. The clamshell computer as defined inclaim 1, wherein the rear enclosure includes isolating members that aredesigned to thermally isolate the thermal attachment from the rearenclosure, the isolating members including one of the following:recesses and patterned conductive sheet.
 4. The clamshell computer asdefined in claim 1, wherein the rear enclosure includes thermal ridgesdisposed on an inner surface of the rear enclosure, the thermal ridgesbeing designed to decrease thermal resistance to the rear enclosure,increasing heat flow to the rear enclosure.
 5. The clamshell computer ofclaim 1, wherein the thermal attachment comprises graphite.
 6. Theclamshell computer of claim 1, wherein the thermal attachment comprisesa sheet highly conductive in a flat X-Y direction and moderatelyconductive in a thin Z direction.
 7. The clamshell computer of claim 1,wherein the thermal attachment is configured to steer heat away from thevideo controller towards corners of the top housing.
 8. The clamshellcomputer of claim 1, wherein the video controller has a hotspot formingcontact area, wherein the thermal attachment is isolated from thehotspot forming contact area.
 9. A housing comprising: one or moreelectrical components that are disposed at the housing; a thermalattachment that is designed to transfer heat generated by the one ormore electrical components; and a rear enclosure that is designed toengage the thermal attachment, the rear enclosure being further designedto receive and dissipate the received heat from the thermal attachment,wherein the one or more electrical components include a video controllerand a display device, the video controller being electrically coupled tothe display device, the video controller being placed between thethermal attachment and the display device.
 10. The housing as defined inclaim 9, wherein the thermal attachment covers a portion of an innersurface area of the rear enclosure and is made of materials capable ofdistributing temperature.
 11. The housing as defined in claim 9, whereinthe thermal attachment includes a pattern of perforations that isdesigned to steer heat towards the corners of the rear enclosure. 12.The housing as defined in claim 9, wherein the rear enclosure includesisolating members that are designed to thermally isolate the thermalattachment from the rear enclosure.
 13. The housing as defined in claim12, wherein the isolating members includes recesses and patternedconductive sheet.
 14. The housing of claim 9, wherein the thermalattachment comprises graphite.
 15. The housing of claim 9, wherein thethermal attachment comprises a sheet highly conductive in a flat X-Ydirection and moderately conductive in a thin Z direction.
 16. Thehousing of claim 9, wherein the thermal attachment is configured tosteer heat away from the video controller towards corners of thehousing.
 17. The housing of claim 9, wherein the video controller has ahotspot forming contact area, wherein the thermal attachment is isolatedfrom the hotspot forming contact area.
 18. A top housing of a clamshellcomputer comprising: a display device that is disposed at the tophousing; a thermal attachment that is designed to transfer heatgenerated within the top housing; a rear enclosure that is designed toengage the thermal attachment, the rear enclosure being design todissipate the heat received from the thermal attachment; and comprisinga video controller that is electrically coupled to the display device,the video controller being placed between the thermal attachment and thedisplay device.
 19. The top housing as defined in claim 18, wherein thethermal attachment covers a portion of the inner surface area of therear enclosure and is made of materials capable of distributingtemperature, the thermal attachment including a pattern of perforationsthat is designed to steer heat towards the corners of the rearenclosure.
 20. The top housing as defined in claim 18, wherein the rearenclosure includes isolating members that are designed to thermallyisolate the thermal attachment from the rear enclosure, the isolatingmembers including one of the following: recesses and patternedconductive sheet.
 21. The top housing of claim 18, wherein the thermalattachment comprises graphite.
 22. The top housing of claim 18, whereinthe thermal attachment comprises a sheet highly conductive in a flat X-Ydirection and moderately conductive in a thin Z direction.
 23. The tophousing of claim 18, wherein the thermal attachment is configured tosteer heat away from the video controller towards corners of the tophousing.
 24. The top housing of claim 18, wherein the video controllerhas a hotspot forming contact area, wherein the thermal attachment isisolated from the hotspot forming contact area.
 25. A clamshell computercomprising: a base; and a top housing that is attached to the base viaat least one hinge, the top housing including a thermal attachment thatengages a rear enclosure of the top housing, the thermal attachmentbeing designed to conduct heat towards the rear enclosure, wherein therear enclosure includes thermal ridges disposed on an inner surface ofthe rear enclosure, the thermal ridges being designed to decreasethermal resistance to the rear enclosure, increasing heat flow to therear enclosure.